Just a pipe - rejet ?

[Guest]

Hi Guys -

I haven't had my '83 GS1100E all that long yet - it has the stock airbox/filter, and an aftermarket 4-into-1 header.

If I roll on the throttle it's got a lean stumble between about 5300 & 5800 rpm, and then it smooths out and accelerates hard again.

In past experience on my KZ's just putting on a pipe wouldn't lean them out hardly at all, but then again, Kawasaki wasn't getting as much power out of their mills either.

So whaddya think - do you guys have to rejet for a pipe ?

And while I'm at it, should I justr go ahead and put in the dynojet kit with the needles, etc ?

[Steve]

Yes and yes.

Depending on the pipe and how restrictive (quiet) it is, you will still have to re-jet.

For the best performance and easiest time getting there, the DynoJet kit is highly recommended.

.

[1_v8_merc]

Most of the GS bikes were Jetted towards the Lean side anyways.
(some people say it's said due to emissions...since Leaner is better emissions-wise.)

So that usually leaves Little-to-none room for modifications...without re-jetting the Mains of course.

My 750 has kerker 4-1 and a glasspack, and doesn't run Lean at all all through the RPM band....

[chef1366]

I'd put a 47.5 pilot jet and 120 main jet in and remove the airbox lid.
I'd also shim the jet needle a bit.

[Montanaman]

~update~

I had forgotten the joys of figuring out a new/used bike -

I got my DYNOJET kit -

First I took off the tank/hoses, and then drained the gas out of the carbs-

Then as I loosened the clamps, I saw what appeared to be two new boots - and something clicked in my head, and I looked for mixture screws, and saw the covers had been carefully removed - so I knew somebody had these carbs off in the not so distant past -

Pulling off the bowls, I see a set of DJ114 main jets, and pulling out the slide there's a classic DYNOJET needle -

So I'm thinking now that what I'm seeing isn't a lean 'stumble' but maybe a rich 'burble' and I'm going to put in the DJ110 jets and see what they do.

Keep you posted.

[koolaid_kid]

You have a stage 1 DynoJet kit already installed. I agree it sounds like the main is too large. Plug chops or a Wideband will tell you if it is. Personally, I would try to lean out the mixture first by removing the airbox lid and possibly adjusting the needle position as Chef suggests. If that does not work, then I would juggle the main size.
I contacted Dynojet and the jets are only $2 each plus shipping. I suggest you contact Dynojet and see if they will take the kit back and just get different jets, since you already have a kit installed.
Also check your float level while you have the carbs off. I have rebuilt 2 sets of carbs and both had incorrect float level settings.

[Montanaman]

Thanks Koolaid Kid -

I checked the float levels, and replaced the DJ114's with the DJ110's, and now my bike carburetes much better.

It idles the same, and the throttle response is the same (Good) but when I crank it wide open it accelerates hard, right up and through where it was stumbling.

I also notice, that right about that point, 5200 rpms, the bike hits the sweet spot of its powerband.

I bought my kit on EBAY from a wholesaler, so I've basically got a complete kit now, with 2 sets of DJ114 jets and no DJ110's, so I'll put them on the for sale list on this forum and make somebody a good deal on it.

I'll never try a stage 3 kit, because over the years on my KZ's I was never happy with the way pod filters carbureted, and I ended up putting the airboxes back on the two bikes I tried them on.

I'm happy.